The invention relates to the field of medical devices, and more particularly to catheters, such as needle catheters or other elongated devices configured for inserting into a patient's body lumen to perform a diagnostic or therapeutic procedure, such as delivery of an agent to the coronary or peripheral vasculature.
The delivery of therapeutic agents into various parts of the vascular system has been shown to be an effective method of treating vascular disease. A variety of agents can be delivered including anti-proliferative, anti-inflammatory, anti-neoplastic, anti-platelet, anti-coagulant, anti-fibrin, anti-thrombotic, anti-mitotic, antibiotic, anti-allergic, and antioxidant compounds. To treat a diseased section of the vessel, these agents could be delivered directly into the vessel wall adjacent to the diseased section, and/or into the periadventitial (perivascular) space. Vascular regenerative therapies, such as the delivery of mesenchymal stem cells, require the delivery of a bolus of biologic materials into a portion of the vascular system such as into the tissue surrounding a coronary vessel. Local, as opposed to systemic delivery is a preferred method of treatment in that smaller total levels of medication are administered in comparison to systemic dosages yet are concentrated at a specific site. As a result, local delivery produces fewer side effects and achieves more effective results.
A variety of methods and devices have been proposed for percutaneous drug delivery to a diseased region of the vasculature, including catheters having a needle configured to be directed out of the catheter and into the vessel wall to deliver the desired agent to the tissue. In order to properly position the distal end of a drug delivery catheter in a patient's tortuous distal vasculature, the catheter should preferably have a low-profile, flexible distal section despite also having the necessary structural components required for the drug delivery at the operative distal end of the catheter. However, these are often competing considerations, making it difficult to provide the necessary operative distal end while still having good deliverability (i.e., ability to track within the patient's vasculature to a desired location therein).